6 files changed, 111 insertions, 0 deletions
diff --git a/src/mainboard/prodrive/atlas/Makefile.inc b/src/mainboard/prodrive/atlas/Makefile.inc
index 1446e54c25d8..3826c8f654bd 100644
--- a/src/mainboard/prodrive/atlas/Makefile.inc
+++ b/src/mainboard/prodrive/atlas/Makefile.inc
@@ -1,5 +1,7 @@
 ## SPDX-License-Identifier: GPL-2.0-only
 
+all-y += ec.c
+
 bootblock-y += bootblock.c
 bootblock-y += early_gpio.c
 
diff --git a/src/mainboard/prodrive/atlas/bootblock.c b/src/mainboard/prodrive/atlas/bootblock.c
index 5b1643b74280..07f3bb2bde15 100644
--- a/src/mainboard/prodrive/atlas/bootblock.c
+++ b/src/mainboard/prodrive/atlas/bootblock.c
@@ -1,10 +1,16 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #include <bootblock_common.h>
+#include <types.h>
 
+#include "ec.h"
 #include "gpio.h"
+#include "mainboard.h"
 
 void bootblock_mainboard_early_init(void)
 {
 	configure_early_gpio_pads();
+
+	/* Enable EMI (Embedded Memory Interface) 0 on the EC */
+	ec_espi_io_program_iobase(EC_IDX_PORT, EMI_0_IOBASE_INDEX, EMI_0_IO_BASE_ADDR);
 }
diff --git a/src/mainboard/prodrive/atlas/devicetree.cb b/src/mainboard/prodrive/atlas/devicetree.cb
index e9c818106f9a..1c4af586a92c 100644
--- a/src/mainboard/prodrive/atlas/devicetree.cb
+++ b/src/mainboard/prodrive/atlas/devicetree.cb
@@ -13,6 +13,8 @@ chip soc/intel/alderlake
 	register "gen2_dec" = "0x000c0201"
 	# EC memory map range is 0x900-0x9ff
 	register "gen3_dec" = "0x00fc0901"
+	# EC EMI 0 range is 0xc00 - 0xc0f
+	register "gen4_dec" = "0x000c0c01"
 
 	# SaGv Configuration
 	register "sagv" = "CONFIG(ATLAS_ENABLE_SAGV) ? SaGv_Enabled : SaGv_Disabled"
diff --git a/src/mainboard/prodrive/atlas/ec.c b/src/mainboard/prodrive/atlas/ec.c
new file mode 100644
index 000000000000..cb022dbc880d
--- /dev/null
+++ b/src/mainboard/prodrive/atlas/ec.c
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#define __SIMPLE_DEVICE__
+
+#include <arch/io.h>
+#include <device/pnp.h>
+#include <device/pnp_ops.h>
+#include <types.h>
+
+#include "ec.h"
+
+/* 10.7.2 ENABLE CONFIG MODE */
+static void pnp_enter_conf_state(const pnp_devfn_t dev)
+{
+	const u16 port = dev >> 8;
+	outb(0x55, port);
+}
+
+/* 10.7.3 DISABLE CONFIG MODE */
+static void pnp_exit_conf_state(const pnp_devfn_t dev)
+{
+	const u16 port = dev >> 8;
+	outb(0xaa, port);
+}
+
+void ec_espi_io_program_iobase(const u16 port, const u8 iobase_index, const u16 base)
+{
+	const pnp_devfn_t dev = PNP_DEV(port, LDN_ESPI_IO_COMPONENT);
+
+	pnp_enter_conf_state(dev);
+	pnp_set_logical_device(dev);
+	pnp_write_config(dev, iobase_index + 2, (base & 0x00ff) >> 0);	/* Addr LSB */
+	pnp_write_config(dev, iobase_index + 3, (base & 0xff00) >> 8);	/* Addr MSB */
+	pnp_write_config(dev, iobase_index + 0, base != 0x0000);	/* Valid bit */
+	pnp_exit_conf_state(dev);
+}
+
+/* TABLE 14-5: RUNTIME REGISTER SUMMARY */
+#define HOST_EC_MBOX		0x00
+#define EC_HOST_MBOX		0x01
+#define EC_ADDRESS_LSB		0x02
+#define EC_ADDRESS_MSB		0x03
+#define EC_DATA_BYTE(n)		(0x04 + (n) % sizeof(u32))
+#define INTERRUPT_SOURCE_LSB	0x08
+#define INTERRUPT_SOURCE_MSB	0x09
+#define INTERRUPT_MASK_LSB	0x0a
+#define INTERRUPT_MASK_MSB	0x0b
+#define APPLICATION_ID		0x0c
+
+/* 14.8.3 ACCESS TYPES */
+enum emi_access_type {
+	EMI_ACCESS_8_BIT		= 0,
+	EMI_ACCESS_16_BIT		= 1,
+	EMI_ACCESS_32_BIT		= 2,
+	EMI_ACCESS_32_BIT_AUTO_INC	= 3,
+};
+
+void ec_emi_read(u8 *dest, const u16 base, const u8 region, const u16 offset, const u16 length)
+{
+	const u16 addr = ((region & 1) << 15) | (offset & 0x7ffc) | EMI_ACCESS_32_BIT_AUTO_INC;
+
+	outb((addr & 0x00ff) >> 0, base + EC_ADDRESS_LSB);
+	outb((addr & 0xff00) >> 8, base + EC_ADDRESS_MSB);
+
+	/* EC_ADDRESS auto-increment happens when accessing EC_DATA_BYTE_3 */
+	for (u16 i = 0; i < length; i++)
+		dest[i] = inb(base + EC_DATA_BYTE(offset + i));
+}
diff --git a/src/mainboard/prodrive/atlas/ec.h b/src/mainboard/prodrive/atlas/ec.h
new file mode 100644
index 000000000000..bad990434011
--- /dev/null
+++ b/src/mainboard/prodrive/atlas/ec.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef MICROCHIP_MEC152X_EC_H
+#define MICROCHIP_MEC152X_EC_H
+
+/*
+ * Used references: MEC152x datasheet (Microchip document DS00003427C)
+ */
+
+#include <types.h>
+
+/* TABLE 3-1: BASE ADDRESS */
+#define LDN_ESPI_IO_COMPONENT	0xd
+
+/* TABLE 9-6: ESPI I/O BASE ADDRESS REGISTER DEFAULT VALUES */
+#define EMI_0_IOBASE_INDEX	0x68
+#define EMI_1_IOBASE_INDEX	0x6c
+
+void ec_espi_io_program_iobase(const u16 port, const u8 iobase_index, const u16 base);
+
+void ec_emi_read(u8 *dest, const u16 base, const u8 region, const u16 offset, const u16 length);
+
+#endif /* MICROCHIP_MEC152X_EC_H */
diff --git a/src/mainboard/prodrive/atlas/mainboard.h b/src/mainboard/prodrive/atlas/mainboard.h
new file mode 100644
index 000000000000..a03cff4f477b
--- /dev/null
+++ b/src/mainboard/prodrive/atlas/mainboard.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef ATLAS_MAINBOARD_H
+#define ATLAS_MAINBOARD_H
+
+/* Embedded controller settings */
+#define EC_IDX_PORT		0x2e
+#define EMI_0_IO_BASE_ADDR	0xc00
+
+#endif /* ATLAS_MAINBOARD_H */